There are extra legal requirements placed on people keeping pet pigs beyond those of dog owners etc! If you keep a pig - even mini-pigs or kune kune etc you need a CPH (County Parish Holding) number for the premises where the pig lives. Also you need to log the route of any planned walks with the Animal He Divisional Office (any other movements require a movement license.
PLUS feeding of waste products containing animal protein is forbidden - this means no waste from the human table! This is important, it helps protect the national pig herd.
see Bown,P 2010 Vet Record May 15, page 631. The Pig Veterinary Society opposes the keeping of pigs as pets.